1. Field of the Invention
The present invention relates generally to transmission of an electronic mail (email) message, through a packet switching network, undergoing facsimile (fax) conversion for conversion thereof to a fax document including a plurality of fax pages for receipt by a fax device(s) and particularly to failed fax transmissions wherein a limited number of fax pages are re-transmitted thereby eliminating the need for transmission of the entire fax document.
2. Description of the Prior Art
With the advent of the use of packet switching networks, such as the Internet, various forms of communications of data, voice, audio or a combination thereof have been integrated to allow for the transfer of information in various forms. For example, recently, electronic mail (email), which is used to transfer text, such as files and messages, audio and video, is commonly employed to transfer information between people and equipment located all over the world. Even more recently, email messages (including attached files at times) are converted to facsimile (fax) documents for receipt by fax devices. The transfer of email messages is generally performed through a packet switching network and at some later time, after the email message has been converted to a fax document, the latter is transmitted through a Public Switching Telephone Network (PSTN), such as the telephone company infrastructure.
In a conventional fax transmission environment where fax documents are exchanged between two fax devices without going through a packet switching network, when a fax transmission fails and a subset of fax pages are not successfully delivered to their intended destination, the failed subset of pages are re-transmitted by a fax user. When the sender fax device fails to successfully send all of the pages of a fax document, the sender re-transmits only the pages which failed to be transmitted, rather than re-transmitting the entire fax document. This is possible due to the availability of memory space for storing the entire fax document within a conventional fax device. There is, thus, no need for re-transmission of the entire fax document.
Prior to the invention, in environments where fax documents are generated from email messages wherein the email message travels through a packet switching network environment and the transmission of the fax document results in failure to deliver a subset of the pages thereof (partial fax delivery), the entire fax document is subsequently re-transmitted. This limitation is, in part, due to the lack of secondary memory (or secondary storage space) within equipment, such as routers, used throughout packet switching network environments. Stated differently, routers do not have adequate storage space to maintain the entire fax document therein. This limitation is further due to limitations associated with the Simple Mail Transfer Protocol (SMTP) protocol, a standard protocol employed in communication of email information between various packet switching network equipment, in which either the entire email message is accepted (successfully transmitted) or the message fails and thus must be re-transmitted in its entirety. Thus, when a failure occurs, the entire fax document is re-transmitted by alerting a mail server, which is also included within the packet switching network environment, to re-transmit the original email message. The router generally does not include sufficient memory storage to maintain all of the packets of the email messages or all of the pages of the fax document. Thus, the router cannot act as a conventional fax device.
Yet another problem associated with the transfer of fax-converted email messages is delivery of the fax document to more than one fax device (fax broadcasting). If transmission to one or more fax recipients fails, the following occurs. The remaining pages of the fax document are sent to those fax recipients that are successfully receiving the fax document and transmission is discontinued to those fax recipients that have failed to correctly receive the fax document. The problem with this approach is that fax broadcast is treated no differently than sending a fax document to only one recipient where the mail server is concerned. That is, the router must notify the mail server to re-transmit the fax document for re-transmission thereof, by the router, to the fax recipients that did not receive the fax document. There is no way of keeping track of which fax recipients successfully received the fax document and which did not. Thus, the same fax document is sent to all of the fax recipients repeatedly and if one or more fax recipients fail to correctly receive the fax document during a repeated transmission, the mail server is notified one more time and the fax document is again re-transmitted to all of the fax recipients. As the reader has probably already noted, this can result in an infinite loop with repeated transmissions of the same document to all of the fax recipients. This problem is exacerbated with more fax recipients, i.e., the more fax recipients, the higher the chances of failing with at least one recipient and therefore the more likely it is to enter into an infinite loop problem. An infinite loop problem is clearly intolerable due to many reasons, among which are: waste of processing power by the router, waste of unnecessary paper by the fax recipients in duplicating the same fax document due to repeated fax transmissions, and the like.
Even if the infinite loop problem described above is avoided due to an eventual successful transmission to all fax recipients, a problem still remains. Namely, some of the recipients will have received multiple copies of the fax transmission as a result of retransmissions triggered by a certain subset of the recipients whose transmissions failed. This results in the problems stated above (i.e., waste of router processing power, waste of paper, etc.), and is once more due to the inability to distinguish between those fax recipients that received the fax document successfully and those that did not.
Therefore, the need arises for an apparatus and method for transmitting, to fax recipient(s), only those pages of a fax document that have failed to have been successfully transmitted to their fax recipient(s), the fax document having been created by conversion of an email message to the fax document, the apparatus and method causing a limited number of transmissions thereby resulting in lower costs and less waste to the user of the fax recipient.